Compression stockings, or socks, are used to treat varicose veins and edema and are often used for post-surgical support to prevent blood clots. They are designed to increase blood flow and provide extra support for the circulatory system of the legs and work by applying graduated pressure to the lower leg and foot.

The pressure applied to the feet, ankles and legs by compression socks forces circulating blood to flow through narrower channels by compressing the muscles, surface veins and arteries. This increases pressure, forcing more blood to return to the heart, rather than pooling at the feet and ankles and causing pain and edema. Compression stockings are used by people suffering from varicose veins and diabetes-related circulation problems, as well as by athletes and pregnant women. They have also become popular among travelers to prevent blood clots from forming during long periods of inactivity in a car or airplane.

Compression socks come in a variety of levels, a physician may be necessary to determine the appropriate level needed. For the lowest compression levels, the appropriate sock size may be determined based on shoe size; however, foot and leg measurements must be taken to determine proper size and style for any other compression levels. For knee-high socks, three measurements must be taken; the ankle just above the bone, the widest part of each calf and the length of the calf from the fold of the knee to the bottom of the heel.

For best accuracy, measurements should be taken barefoot from a standing position by another person and in the morning before legs or ankles swell. Because legs may not be exactly the same size, each leg should be measured and the fit based on the largest measurements. People with very muscular calves will need to select socks which are one size larger than shoe size to avoid putting too much pressure on the leg. Socks should be replaced every four to six months for greatest benefit, as the high strength elastic or nylon used in them can become weaker over time.

Because compression socks can be stretched or damaged in a washer and dryer, they should be laundered by hand and laid flat to dry in a cool or warm place away from heat. Hanging them to dry can stretch them out and should be avoided. The socks should be washed frequently, so it is best to have more than one pair. Although there are some washing solutions available which are specifically designed for compression stockings, any mild soap or detergent can be used.